Cross-protection relay



Filed July 21, 1927 2 Sheets-Sheet 1 Q mu INVENTOR y 1929. c. D. c'RoNK 1,713,489

CROSS PROTECTION RELAY I Filed July 21. 1927 2 Sheets-Sheet 2 d U 3 as gnm'ntot Patented May 14, 1929.

UNITED STATES PATENTOFFICE.

CHARLES D. CRONK, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOB RAIL:

WAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

Application filed July 21,

This invention relates to railway interlocking systems of the electrically controlled electric power operated type, and more particularly to cross protection means for such systems.

For convenience, and in order to simplify the description of the present invention, the term traflic controlling device has been used in this specification to designate any one of the various devices used for controlling the movement of traffic through an interlocking plant, such as power operated signals, switch machines, movable point frogs, derails, and the like. For reasons well known to those skilled in theart of interlocking, it is extremely dangerous to use electric power operated traffic controlling devices if these devices may be operated by unauthorized: current, such as current flowing due to a cross, a ground or the like. Another important requirement in an interlocking system of the usual type where the interlocking mechanism mechanic-ally interlocks conflicting levers in a manner so that they can only be moved to a position not to conflict with routes already set up, is that the control levers in such system must always be in accordance with the position of the traffic controlling device, and the particular system to which the present invention has been shown applied, this correspondence of levers and traflic controlling devices is assured by the provision of locking means on the levers which'is unlocked by dynamically generated current which can only flow after the traflic controlling device has responded to a change in the position of the control lever.

In view of these and other important considerations it is proposed in accordance with the present invention to provide cross protection means which will disconnect the source of current supply only when an unauthorized current flows, that is, provide means which will distinguish between either'regular operating current or dynamic indication current and unauthorized current.

Specifically, it is proposed to provide a cross protection device which consists of a snap action or stick type circuit interupter having three coils arranged on its magnetic 1927.-Se11al No. 207,537.

circuit, and to include one of these coils in the operating circuit controlled by a, lever and include the-third coil in a dynamic indication circuit portion thereof in which snubbing current flows after thetrafliccontrolling devicehas fully responded; and to arm the direction of the turns of these coils sot if current is applied to-the traflic controlling device by the lever the current flowing in the operating coil and the common return wire coil will produce bucking flux in the magnetic circuit of the cross protection device, and that if dynamic indication current flows its flow in the dynamic indication coil and in the common return wire coil produces bucking flux in the cross protection device and therefore does not cause operation of thisdevice. I Consequently, if current is applied through an unauthorized th'to either of the control wires leading to t e traflic controlling .device this current will flow in the coils in such a manner as to cause magnetomotive-forces produced by the current flowing in these coils to be cumulative or at least not complete bucking and cause operation of the cross protection device.

Other objects, purposes and characteristic features of the invention are in part apparent from the drawings and will in part be pointed out in the specification hereinafter.

In describing the invention in detail, reference will be made to the accompanyingdrawings in which Fig. 1 shows a layout view of a track switch operable by a switch machine having an operating circuit arrangement and protecting devices embodying the presentinvention I Fig. 2 shows a side elevation of a cross protection relay embodying the present invention;and v a Fig. 3 shows a front view of the cross protection relay illustrated in Fig. 2.

In the particular arrangementin which the present invention has been illustrated the traflic controlling device heretofore mentioned comprises a switch-machine SM, which has been shown conventionally by its motor ion and pole changer contacts contained within a dotted rectangle. This switch machine may be of any suitable construction, such for instance as shown in the prior patent to Howe No. 1,466,903 dated September a, 1923. This switch machine SM, as shown, is used for operating the switch points of-the switch S associated with the siding and main track illustrated. Although the present invention maybe applied to interlocking systems of various kinds, it has for convenience been shown applied to an interlocking system of the type in which the various conflicting traflic control devices are interlocked by hav ing their respective levers mechanically interlocked, suitable provision being made for maintainingthe lever and the traflic controllingdevices in corresponding position or condition. In ,the arrangement illustrated the lever L is interlocked with its'various conflicting levers '(not shown) bymechanical interlocking mechanism of which thetappet bar 10, which is moved vertically-in response to backward or forward sliding movement of the lever L by means of the roller 11 operating in the slot 12, only has been shown. Associated-with this lever L are contacts 13 and 14 insulated from each other and from the lever incany' suitable manner. This lever has associatedtherewith an indication magnet IM which is adapted to unlock the lever L by moving the latch 15 to aposition'to release the latch bar 16. i This'lever also has a safety magnet SI associated therewith, which in response to the flow of unauthorized current in someinstances will prevent the unlatching of the lever L in spite of flow of current in the indication magnet IM. For a more complete description of the lever and its associated mechanism reference maybe had to the prior patent to-Howe No. 1,163,154 dated Dec. 7, 1915. i

Before further discussing the interlocking system embodying the present invention it is deemed expedient to consider the specific construction of one embodiment of a cross protection relay useable in this system and forming a part of the present invention. Referring to. Fig. 2, the cross protection relay CR, (also conventionally shown in Fig. 1) comprises a bar 20 of magnetic material of inverted L-shape supported against a suitable vertical 'structur'e such as the wall 21 by the bolt 22, a dowel pin 23 being employed for maintaining the relay in a proper vertical position. This bar 20 has its short legs suitably perforated and threaded for supporting the core 24 of magnetic material, locked in position by a lock'nut 25. To the lower end of the core 24 is "fastened a block 26 of magnetic material containing a residual pin 27, constituting the head of ascrew of non-magnetic material. To the lower end of the bar 20 is pivotally secured, by suitable means such as the screw 28, an armature 29 constructed'of suitable soft iron, which armature is limited in its downward movement by an adjutsable stop comprising the screw 30 of non-magnetic material threaded into the block 26. To the magnetic .structnrethus far described is secured a panel 31 of insulating material by suitable means, such as the screws '19. Near,- the m1ddle of the insulating panel 31 are provided bearing locks 32, on which is pivotally mounted by the pin 33 adouble blade knife switch comprisin switch blades 34 and 3% adapted .to engage switch clips 36 and 36, and having an operating handle 38. Pivotally mounted on the same pin 33 is a circuit interrupter or breaker, comprising the main arm 40 having a backwardly projecting ear 40 in which is hooked one end of a tension spring 41 having its other end hooked around the bolt 42 passing through the insulating panel 31. It will thus appear that with the spring .41 tension'ed the main arm a0 is urged away from the panel 31. This main arm 40 is slotted near its end and the bifurcation formed thereby contains a pin 43 which is adapted to be engaged by the hooked end of the latch 44.. The spring41 may however be omitted and the force of gravity together with the kick off tendency of the spring fingers 47 and -17 relied upon, if desired. The main bar 40 has aninsulating block t5, screw fastened thereto by screws 46, to which block are screw fastened spring contact: fingers 47 and 17 in any suitable mann as by screws 48; From this construction it're'adily appears that the attraction of the armature 29 will cause the rod 19 to strike the rear end of the latch 44-, thereby causing the hooked end thereof to disengage the pin 43 so as to permit the'spring 4-.1 to'throw the circuit breaker to its open dotted position, and thereby causing the movable cont-acts 50 and 50* supported by the spring fingers 47 and 47 to disengage their stationary contacts 51 and 51, these contacts 50.50 and 51+51 being made of suitable metallic or refractory conducting and are resisting material. The contacts 51 and. 51 are supported by the terminal posts 52 and5 2. With the cross protection relay in its normal circuit closing position the binding posts 52and 54 are electrically connected'through the medium of switch block 34 and the flexible connectionor pigtail 55, the. same being true of posts 52 and 5 By looking at Fig. 2 it readily appears that if the circuit interrupter actuated to cause its contacts to assume the open dotted position, that the movement of this circuit interrupter beyond the dotted position is prevent ed by the projection 38 extending from the handle 38. If now, the handle 38 is moved upward so as to reclose the circuit'breaker, the double pole switch including'blades 3% and 34 is opened before the circuit breaker contacts 5051 and 50 51 are closed. In practice, the cross protection relay is so housed that the handle 38 is only accessible, and therefore the contacts 50'51 cannot be reclosed having once opened without first opening the contacts 3436 and M -36. In other words, it is impossible for the operator to hold the circuit which is to be protected by this cross protection relay, closed by brute force, because if he is holding the handle in one extreme position the contacts 34.36 are open and if held in the other extreme, or normal position, the contacts 50-51 may be automatically opened by actuation ofthe armature 29.

In the specific typeof cross protection relay shown there are contained on the magnet core 24 three separate coils 60, 61 and 62, and if the sum of the fluxes and the polarities thereof'due to the current flowing in these coils 60, 61 and 62 is sufiicient to attract the armature 29 the circuit interrupter is operated and the circuits in which the contacts 51 and 5()51 are contained are opened.

Referring now to Fig. 1 in which the cross protection relay shown in Figs. 2 and 3 have been conventionally illustrated, it should be noted that the coil is contained in the main battery lead leading to the contacts of the lever L and including the safety magnet SI, that the coil 61 is included in'the indication branch of the circuit for controlling the switch machine SM, and that the coil 62 is contained in the common return wire C of the switch machine circuit. In practising the invention, the number of turns "and the size of the wire used in each of these coils 60, 61 and 62 is preferably the same, but if desired there may be a sufficient difference between the turns in these coils so as to have a differential eifect on the armature 29, which will cause i 1 the cross protection relay to be operated when the current flow is excessive.

In order to obtain a clear understanding of the present invention it is deemed expedient to consider certain steps in the operation of the switch machine SM in response to movement of the lever L, and in order to do so let us assume that it is desired to move the switch S to the siding position. In order to do this the operator pulls the lever from the normal position as indicated by the letter N to the half reverse position as indicated by the letters HR, the lever cannot be pulled out beyond the half reversed position because this is prevented by the latch bar 16. lVith the lever in the half reverse position a circuit for operating the motor of the. switch machine SM is completed, which may be traced as follows :beginning at the battery B coil 60 of the cross protection relay CR, windings of the safety magnet SI, wire 63, contacts 1364, wire 65, reverse wire RWV, contacts 6667, wires 68 and 69, armature of the motor M, wires 70 and 71, pole changer contacts 72 73, wire 7 4, field winding 75 of the motor M, wire 76, common re- CR does not-cause operation of the same because the direct-ions of the magneto-motiveforces setup in the coils 60 and 62 are opposite each other as indicated by the solid arrows. As soon as the switch machine motor has completed the operating stroke of the switch machine SM the pole changer contacts 67 and 73 are quickly shifted ,to the dotted position, and this reverses the'co'nnections of the armature'of the motorM and causes this motor to act as a series generator and causes the flow of dynamic indication current in the following circuit. Beginning at the armature of the motor M, wire .69, pole changer contacts 7380, wires 81, field winding 7 5 of the motor M, winding 76, common return wire 0, coil 62 of the cross protection relay CR, coil 61 of this same relay, wire 82, coils of the indication magnet IM, wire83, contacts 14-84 of the lever L, wire'85, normal wire NW, contacts 67-86, wire 70 back to the armature of the motor M.- The flow of this dynamic indication current in the coils 61 and 62 of the cross protection relay CR will not cause operation of this relay because the direction of the magneto-motiveforces in these coils, as indicated by the dotted arrows, are opposite and therefore will effectively neutralize each other. The fiow of indication current in the circuit just traced causes the indication magnet IM to attract its armature thereby operating the latch 15 to unlatch the latch bar 16, which permits the lever L-to be moved from the half reverse position to the full reverse position, as indicated by the letter R. In like manner operation of the lever from the full reverse position R to the half normal posi-- tion HN will cause an operating circuit analogous to the operating circuit heretofore traced to be completed, and causes the switch machine to be returned to its normal position. By reason of the similarity in these circuits and their functions it is believed unnecessary to trace the normal operating circuit and the normal indication circuit.

Asjust pointed out in connection with the tracing of the operating circuit and the indication circuit, the cross protection relay OR is not operated due to the flow of operating current supplied by the lever, nor is it operated due to the flow of dynamic current flowing in the indication circuit.

The batter B is not necessarily but presumably used as a source of current supply for operating other traflic control devices similar to'the switch machine SM, and for this reason itis possible for one 'of the control wires such as the wire RlV to be connected to the positive side of this battery B 7 through an unauthorized circuit portion 'or path which may include a portion of one of the control wires of another traffic controlling device by reason of a cross, or the like. It now for this or any other reason the up per terminal preferably the positive side of the battery B is connected to the wire Rl V through an unauthorized circuit portion current may flow due to this unauthorized connection through the two following paths in multiple assuming the lever and switch macation magnet IM, wire 82, coil 61, wire 77, which wire through contacts -5l is connected to the negative side of the battery B. It should be noted, that the flow of unauthorized current in these two paths in multiple will cause their fluxes in coils and G2 to be cumulative, thereby causing attraction of the armature 29, which through the medium of rod {l9 unlatches the member i land causes the contacts 5051 to be opened.

In practice, the contacts 505l may be used to disconnect both the positive and negative side of the battery B, or other source of energy, as far as the circuitarrangement oi the particular traflic controlling device is concerned, or may be used to disconnect the operatlng energy from the entire interlocking system, so that none of the signals of the interlocking system may be cleared until the troublehas been found and rectified, but in order to simplify the clrcult arrangement of r the present invention only a single pair of contacts have been shown in Fig. 1 ot the drawings, and these contained in the negative side of the circuit leading to battery B, although two pairs of contacts are shown in Fig. 3.

The cross protection relay CR embodying the present invention is designed to be very quick acting, and flux therein exerts a heavy force on the armature 29 in response to the flow of unauthorized current by reason of the cumulative effect of the two coils in which such current may flow and therefore removes the source of energy before the motor M of the traflic controlling device. has started to operate. In practice it has been found that the motor in a switch machine under the conditions assumed would not operate far enough to even unlock the lock mechanism (not shown) but disclosed in the switch machine of Patent No. 1,466,903 above mendynamic current, there are two'coils buclc- 7 ing each other. The net result is that a short or open in any one 0011 would causeoperation of the cross protectmn relay, and such operation of the relay would persist until proper repairs have been made. The number of turns in each of the coils 60, 61 and 62 is preferably the same, but if operation. due to excessive or overload operating'current is desired the coil 60 may have a different numher-of turns than coils 61 and 62.

Having thus shown and described one specific embodiment of a circuit arrangement for operating traflic controlling device in an interlocking system and protecting such circuit by a cross protection relay responsive if the current flowing from and to the source of energy are unbalanced to a predetermined extent and responsive if the current in the indication magnet and the common return wire are unbalanced to a predetermined ex tent it is desired to be understood that the particular circuit arrangement in connection with which the inventionhas been illustrated is merely a typical illustration of how the invention may be applied,.and that the specific cross protection relay shown has'merely been illustrated to show how a cross protection relay employing the principles of the present invention may be constructed, and specifically may be constructed so that it cannot be forcibly held inits circuit closing position by the operator; and that the specific illustration of the invention is susceptible of modification to adapt the same to the particular type of traffic controlling device and the particular type of interlocking system to which it is to be applied,all without departing from the scope of the invention or the idea of means underlying the same. 7

hat I desire to secure by Letters Patent tained in the indication circuit portion, and

the third coil contained in the common return wire; said three coils having their turns so arranged that opposed magneto-motiveforces are set up Vin-said core when control current flows in said operating circuit or dynamic indication current flows in said dynamic indication c rcuit.

2. An interlockingsystem comprisin an.

1- electric power operated traflic controlling device, an operating circuit for said device including a control wire and a common return wire; a dynamic indication circuit including a dynamic indication circuit portion and said common return wire in series; a cross protection device having a magnetic circuit including anal-mature; a source of current; means for disconnecting said source of current when said armature is operated; and coils associated with said magnetic circuit and so connected in said operating circuit and in said dynamic indication circuit that said cross protection device is not operated due to the flow of operating current or dynamic indication current, but is operated it unauthorized current is applied to the control wire leading to said trafiiccont-rolling device.

3. In an interlocking system; the combination with an electric power operated traflic controlling device including a motor; a source of electrical energy for operating said device a control circuit for said device including a control wire, a return wire, said motor, said source of current and a contact controlled by a. lever; and an electro-responsive cross protection device which if actuated disconnects said source of energy from said control circuit; said cross protection device including two windings, one of which is contained in said control wire and the other of which is contained in said return wire; said windings having their turns so arranged that current flowing in said control circuit set-s up opposing magneto-motive-forces in said cross protection device; whereby if unauthorized current is applied to said motor in some other way than throu h said control circuit'said cross protection device is operated.

4. In an interlocking system; the combination with an electric power operated traflic controlling device including a motor; a source of electrical energy for operating said device; a control circuit for said device including a control wire, a return wire, said motor, said source of current and contacts controlled by a lever; and an electro-responsivecross protection device which it actuated disconnects said source of energy from said control circuit; said cross protection device including two windings, one of which is connected in said control wire and the other of which is contained in said return wire between the contact of said lever and said source of energy; and said windings having their turns so arranged that current flowing in said control circuit sets up opposing magneto-motive-forces in said cross protection device; whereb, if unauthorized current'is supplied to sai motor from a point beyond the contacts of said control lever. current will flow in said circuits and'coils to cause actua t1on of said cross protection device.

5. In an interlocking system; the combina tion with an electric power operated traflic controlling device including a motor; a source of electrical energy for operating said device; a control circuit for said device including a control wire, a return wire, said motor, said source of current and a contact controlled by a lever; and an electro-responsive cross protection device which if actuated disconnects said source of energy from said control circuit; said cross protection device including a 6. A cross protection relay for interlocking systems for railways comprising, a core, an armature included in a magnetic circuit with said core, and a circuit portion including two coils on said core in series, said coils having their turns so arranged that the magneto-motive forces induced therein effectively neutralize each other.

7 A cross protection relay for interlocking systems for railways comprising, a core, an armature included in a magnetic circuit with said core, and a circuit portion including a source of energy and two coils in series, said two coils being connected respectively in the two lead wires of said source and having their turns so arranged that the flow of currentrin said circuit portion will induce opposing magneto-motive-forces in said magnetic circuit.

8. A cross protection'relay comprising a magnetic circuit including a core and an armature, two coils difl'erently connected con tained on said core, normally closed circuit closing means operated upon attraction of said armature, a handlefor manually reclosing said circuit closing means, and other circuit closing means connected in series with said first mentioned circuit closing means which must be opened before the first mentioned circuit closing means can be closed by operation of said handle.

9. In an interlocking system of the dynamic indication type having an operating circuit and an indication circuit, the combination with a source of current for operating a traflic controlling device through said operat- 6 l nea e ing circuit, across protection relay having three coils linking the magnetic circuit thereof, the first of said coilslbeing connected in series with the second of said coils in said operating circuit so that the magneto-motive forces of said operating circuit neutralize each other, and the first of said coils being connected in series with the third coil in the indication circuit so that the magneto-motive forces of the indication current flowing therer 10 in neutralize each other.

In testimony whereof I afiix my signature CHARLES D. oRoN 

